There are about 40 known families of catfishes–give or take a few extinct families and a few mystery species (which will probably be classified as their own families in time). The largest family of catfish in terms of diversity is the Loricariidae family—the exquisite armoured catfishes of Central and South America. Nearly seven hundred species are known, and more are being added all of the time. The extraordinarily successful family is characterized by suckermouths for closely grazing on vegetation and detritus. They have long slender tapering forms with heavy bony plates around the head and body. The Locariidae frequently have exquisite fanlike dorsal fins which they can open for display (the dorsal fin is the top fin, which you can see extended in some of the “out-of-the water pictures in the gallery below). In Fishes of the World Joseph S. Nelson describes additional armament carried by this family, “When present, the adipose fin usually has a sharp spine at the forward edge.” Because of the vagaries of the Amazon and the other tropical rivers they inhabit, Locariidae are adept at breathing air and can survive for more than a day out of the water.

In addition to their maxillary barbells, which are loaded with sensory organs, the Locariddae are completely covered with taste buds. The fish are therefore extraordinarily attuned to changes in their environment. Even their fins and tails have tasting sensors. Pretty much the only part of the fish’s external body not covered with taste buds are their eyes, which are remarkable in their own right. Locariidae (save for one subfamily) have highly adjustable omega shaped pupils which give them excellent vision in night or day (additionally, to my way of thinking, they further enhance the creatures’ already endearing personality.) The male catfish are loyal parents. In most armoured catfish species, fathers will guard the eggs until they hatch–and they will frequently stick around to defend the larval hatchlings after that.

Hypostomus plecostomus

Aquarists will instantly recognize the family for a famous member, Hypostomus plecostomus, which find service as algae eaters in many tropical hobby tanks. Most specimens of the Loricariidae for sale at aquarium shops are colloquially known as “Plecostomuses”, “plecos”, “suckermouths” or ”algae eaters”. A glimpse at the list of Locariidae species from the “CATelog” of “Planet Catfish” will reveal why these catchall terms are used. I have included a random sampling of these fish from images I found at “Planet Catfish” (I tried hard to correctly cite the photographers and spell the fish names right). You should visit that site and check out these amazing successful animals in their spell-binding diversity.